A team at the University of Nottingham has developed an innovative test to measure the airtightness of buildings. The PULSE test determines the infiltration rate of cold air and the loss of heated air through gaps and cracks in a building, making it possible to create targeted strategies for eliminating drafts which in turn leads to greater energy efficiency and reduced heating bills. The PULSE test also illustrates when a building is too airtight, as too little ventilation can lead to poor indoor air quality.

The PULSE test has been in development at the University of Nottingham for fourteen years and is now being commercialized as an more accurate and convenient alternative to the industry standard “blower door” technique. The PULSE test creates a low-pressure pulse throughout an entire building by releasing a short burst of air. The test takes a few seconds and creates minimal disruption for building occupants and construction workers. The PULSE test is also quick and easy enough for construction workers to perform several times before a building is complete.

In contrast, the “blower door” test takes fifteen to thirty minutes and is usually only used at the completion stage, making it difficult to implement any significant change based on the results of the test.

In a blower door test, a powerful fan mounted into the frame of an exterior door pulls air out of a building. This temporarily lowers the air pressure inside, leading to higher outside air pressure flowing in through all unsealed cracks and openings.

The blower door originated as a research tool in the early 1970’s, simultaneously invented by two groups independently studying the contribution of air leakage to heat loss in residential buildings. The first commercial blower door unit hit the market in 1980.

Regardless of which test is used, determining the airtightness of a building is a crucial step in any energy audit. For homeowners without access to professional equipment, it is possible to at least find leaks, if not measure them, by using a powerful box fan or even a fog machine.